This proposal addresses Strategic Action Plan specifically for S5.06 SBIR area: Space Weather Instrumentation. A Space Weather (SW) array of 4 CubeSats released from a standard 6U deployer are each linked through the Globalstar constellation (much capacity) to provide near real-time ionospheric forecasting. Each CubeSat provides low-latency connections via space-space links in a redundant, time-ordered and common database (O2R) for prompt 24/7 data with a latency of seconds. The proposed Phase 1 study looks at providing instrumentation for analytic model validation that includes several proven SW instruments: energetic particle detector, plasma probe, an IR cooled grid imager, a magnetometer, and GPS. Each of the 4 CubeSat strings include four 20cm solar/plasma foldouts that separate the relatively noisy ThinSat Bus section from the quiet and cooled ThinSat Payload section to improve sensor performance. The 6U array of 4 CubeSats would be staggered in orbit via drag variations to give pole-to-pole orbit data every 12 minutes on average and in situ drag data at affordable cost in the 100 to 700 km orbit region. Prompt and Multipoint SW sensors would improve rapid forecasting and understanding new energy transfer with the goal to deliver end-user action (2018 Space Weather Phase 1 Benchmarks Report from the Presidents National Science and Technology Council). Feasibility: NSL has recently successfully flown the first 60 CubeSat (ThinSats) array with articulating foldouts, particle detectors, IMU, IR imager, and Globalstar links as a demonstration project released from an NG-11 rocket to the ISS on April 17, 2019 (SSC19-S2-08, 2019). NSLhas 400 subsystems in orbit with 100% success and currently delivering 10 CubeSats for launch in 2020. The six Phase 1 results include: 1) Requirements, 2) SW Sensor Trade-Space matrix, 3) Existing Bus revisions, 4) Functional Prototype, 5) Balloon Flight of one CubeSat string (TRL=6), and 6) Final Report. Potential NASA Applications (Limit 1500 characters, approximately 150 words) Will provide new data driven operational forecasting tools to validate models Will pioneer a new spacecraft architecture with ThinSat strings or trains Will provide radiation environment to improve aircraft safety. Underexplored Sun-Earth coupling region explored between 100 to 350 km Forecasting Atmospheric drag with direct measurements above 100km. Study reentry region above 100km Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words) 1. Potential blackout impulses (large Solar Flare energetic particles, geomagnetic storms, meteors, or an EMP pulse). SWAP-E will add new Prompt real time data and critical mapping. 2. SWAP-E ThinSat Sat array concept ideal for Lunar orbit and planetary experiments 3. Advanced Manufacture of ThinSat String or Trains consisting of a stiff solar array foldout is a new architecture